Effect of caffeine on meiotic maturation of porcine oocytes

This study was conducted to evaluate the effect of caffeine on the meiotic maturation of porcine oocytes. Oocyte–cumulus complexes were collected from slaughterhouse-derived ovaries and cultured for 24, 32 or 48 h in medium 199 supplemented with 10% fetal calf serum, 10 μg/ml FSH, 50 μg/ml sodium pyruvate and 50 μg/ml gentamicin in the presence or absence of 2.5 mM caffeine. Caffeine inhibited the meiotic resumption of pig oocytes effectively after 24 h of culture, and 95.5% of oocytes were arrested at the germinal vesicle (GV) stage (control 17.8%, p<0.05). Prolonged culture with caffeine up to 32 h or 48 h, however, resulted in a significant decrease in the inhibitory effect (GV: 13.8% and 8.2%). The number of oocytes at metaphase II after 48 h of culture in the presence of caffeine was significantly lower than that in the control medium (65.3% vs 94.7%, p<0.05). The withdrawal of caffeine after 24 h of culture resulted in the resumption of meiotic maturation, and the oocytes reached metaphase II after 48 h. However, the ability of caffeine-treated oocytes to develop to blastocysts after artificial activation was lower than that of the control (5.5% vs 9.1%, p<0.05). Caffeine treatment significantly increased cAMP levels in the oocytes after 24 h of culture, while both Cdc2 kinase and MAP kinase activation were inhibited in the oocytes. These results suggest that caffeine, similarly to other purine derivatives, prolongs the meiotic arrest of porcine oocytes at the GV stage, perhaps by its action of increasing the cAMP level and by the suppression of Cdc2 kinase and MAP kinase activities in the oocytes.

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Dissociation of MAP kinase activation and MPF activation in hormone-stimulated maturation of Xenopus oocytes

Development ◽

10.1242/dev.126.20.4537 ◽

1999 ◽

Vol 126 (20) ◽

pp. 4537-4546 ◽

Cited By ~ 4

Author(s):

D.L. Fisher ◽

T. Brassac ◽

S. Galas ◽

M. Doree

Keyword(s):

Map Kinase ◽

Xenopus Oocytes ◽

Kinase Activity ◽

Early Response ◽

Meiotic Maturation ◽

Cdc2 Kinase ◽

Kinase Activation ◽

Cell Cycle Activation ◽

Map Kinase Phosphatase ◽

Universal Mechanism

MAP kinase activation occurs during meiotic maturation of oocytes from all animals, but the requirement for MAP kinase activation in reinitiation of meiosis appears to vary between different classes. In particular, it has become accepted that MAP kinase activation is necessary for progesterone-stimulated meiotic maturation of Xenopus oocytes, while this is clearly not the case in other systems. In this paper, we demonstrate that MAP kinase activation in Xenopus oocytes is an early response to progesterone and can be temporally dissociated from MPF activation. We show that MAP kinase activation can be suppressed by treatment with geldanamycin or by overexpression of the MAP kinase phosphatase Pyst1. A transient and low-level early activation of MAP kinase increases the efficiency of cell cycle activation later on, when MAP kinase activity is no longer essential. Many oocytes can still undergo reinitiation of meiosis in the absence of active MAP kinase. Suppression of MAP kinase activation does not affect the formation or activation of Cdc2-cyclin B complexes, but reduces the level of active Cdc2 kinase. We discuss these findings in the context of a universal mechanism for meiotic maturation in oocytes throughout the animal kingdom.

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MAP kinase does not inactivate, but rather prevents the cyclin degradation pathway from being turned on in Xenopus egg extracts

Journal of Cell Science ◽

10.1242/jcs.109.1.239 ◽

1996 ◽

Vol 109 (1) ◽

pp. 239-246 ◽

Cited By ~ 10

Author(s):

A. Abrieu ◽

T. Lorca ◽

J.C. Labbe ◽

N. Morin ◽

S. Keyse ◽

...

Keyword(s):

Map Kinase ◽

Degradation Pathway ◽

Cdc2 Kinase ◽

Vitro Assay ◽

Kinase Activation ◽

Egg Extracts ◽

Dependent Protein ◽

Xenopus Egg ◽

Xenopus Egg Extracts

Unfertilized frog eggs arrest at the second meiotic metaphase, due to cytostatic activity of the c-mos proto-oncogene (CSF). MAP kinase has been proposed to mediate CSF activity in suppressing cyclin degradation. Using an in vitro assay to generate CSF activity, and recombinant CL 100 phosphatase to inactivate MAP kinase, we confirm that the c-mos proto-oncogene blocks cyclin degradation through MAP kinase activation. We further show that for MAP kinase to suppress cyclin degradation, it must be activated before cyclin B-cdc2 kinase has effectively promoted cyclin degradation. Thus MAP kinase does not inactivate, but rather prevents the cyclin degradation pathway from being turned on. Using a constitutively active mutant of Ca2+/calmodulin dependent protein kinase II, which mediates the effects of Ca2+ at fertilization, we further show that the kinase can activate cyclin degradation in the presence of both MPF and the c-mos proto-oncogene without inactivating MAP kinase.

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B-Raf-dependent regulation of the MEK-1/mitogen-activated protein kinase pathway in PC12 cells and regulation by cyclic AMP

Molecular and Cellular Biology ◽

10.1128/mcb.14.10.6522-6530.1994 ◽

1994 ◽

Vol 14 (10) ◽

pp. 6522-6530

Author(s):

R R Vaillancourt ◽

A M Gardner ◽

G L Johnson

Keyword(s):

Growth Factor ◽

Protein Kinase ◽

Map Kinase ◽

Protein Kinase A ◽

Pc12 Cells ◽

Kinase Activation ◽

Mitogen Activated Protein ◽

Epidermal Growth ◽

Camp Levels ◽

Kinase A

Growth factor receptor tyrosine kinase regulation of the sequential phosphorylation reactions leading to mitogen-activated protein (MAP) kinase activation in PC12 cells has been investigated. In response to epidermal growth factor, nerve growth factor, and platelet-derived growth factor, B-Raf and Raf-1 are activated, phosphorylate recombinant kinase-inactive MEK-1, and activate wild-type MEK-1. MEK-1 is the dual-specificity protein kinase that selectively phosphorylates MAP kinase on tyrosine and threonine, resulting in MAP kinase activation. B-Raf and Raf-1 are growth factor-regulated Raf family members which regulate MEK-1 and MAP kinase activity in PC12 cells. Protein kinase A activation in response to elevated cyclic AMP (cAMP) levels inhibited B-Raf and Raf-1 stimulation in response to growth factors. Ras.GTP loading in response to epidermal growth factor, nerve growth factor, or platelet-derived growth factor was unaffected by protein kinase A activation. Even though elevated cAMP levels inhibited Raf activation, the growth factor activation of MEK-1 and MAP kinase was unaffected in PC12 cells. The results demonstrate that tyrosine kinase receptor activation of MEK-1 and MAP kinase in PC12 cells is regulated by B-Raf and Raf-1, whose activation is inhibited by protein kinase A, and MEK activators, whose activation is independent of cAMP regulation.

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B-Raf-dependent regulation of the MEK-1/mitogen-activated protein kinase pathway in PC12 cells and regulation by cyclic AMP.

Molecular and Cellular Biology ◽

10.1128/mcb.14.10.6522 ◽

1994 ◽

Vol 14 (10) ◽

pp. 6522-6530 ◽

Cited By ~ 128

Author(s):

R R Vaillancourt ◽

A M Gardner ◽

G L Johnson

Keyword(s):

Growth Factor ◽

Protein Kinase ◽

Map Kinase ◽

Protein Kinase A ◽

Pc12 Cells ◽

Kinase Activation ◽

Mitogen Activated Protein ◽

Epidermal Growth ◽

Camp Levels ◽

Kinase A

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Two pathways control MAP kinase activation during mouse oocyte maturation: One involving mos but not Raf-1, and one releasing the inhibitory effect of protein phosphatases

Biology of the Cell ◽

10.1016/0248-4900(96)81324-4 ◽

1995 ◽

Vol 84 (1-2) ◽

pp. 84-84

Author(s):

Marie-Hélène Verlhac-Chedotal ◽

Jacek Kubiak ◽

Michèle Weber ◽

William Colledge ◽

Martin Evans ◽

...

Keyword(s):

Map Kinase ◽

Oocyte Maturation ◽

Protein Phosphatases ◽

Inhibitory Effect ◽

Mouse Oocyte ◽

Kinase Activation

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Mitogen-activated protein kinase activity and microtuble organisation are altered by protein synthesis inhibition in maturing porcine oocytes

Zygote ◽

10.1017/s0967199400003105 ◽

1996 ◽

Vol 4 (3) ◽

pp. 191-198 ◽

Cited By ~ 13

Author(s):

Maki Inoue ◽

Kunihiko Naito ◽

Taisuke Nakayama ◽

Eimei Sato

Keyword(s):

Protein Synthesis ◽

Map Kinase ◽

Kinase Activity ◽

Germinal Vesicle ◽

Protein Kinase Activity ◽

Protein Synthesis Inhibition ◽

Germinal Vesicle Breakdown ◽

Kinase Activation ◽

Synthesis Inhibition ◽

Mitogen Activated Protein

SummaryPreviously we have shown that mitogen-activated protein (MAP) kinase activity abruptly increases at the first metaphase (M1) and remains significantly higher than that at the germinal vesicle (GV) stage until the second metaphase (M2) in porcine oocytes cultured in vitro. The present paper describes how the mechanism of the blockage of meiotic maturation by protein sythesis inhibition involves MAP kinase regulation. Cycloheximide arrested both germinal vesicle breakdown (GVBD) and the normal transition from M1 to M2. MAP kinase activation was also reduced in these maturation-inhibited oocytes. By using immunofluorescence microscopy with the monoclonal antibody raised against rat α-tubulin, we showed that cycloheximide caused morphological abnormality in a spindle at M1, but not at M2. All these results indicate that in porcine oocytes: (1) GV blockage by protein synthesis inhibition involves the suppression of both histone H1 kinase and MAP kinase activation, (2) during the transition from M1 to M2, maintenance of a normal metaphasic spindle and high MAP kinase activity require protein synthesis, and (3) once the M2 cytoskeletal structures have been completed, and/or after the ‘critical period’, cytostatic factor activity is independent of protein synthesis.

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Microtubule and chromatin behavior follow MAP kinase activity but not MPF activity during meiosis in mouse oocytes

Development ◽

10.1242/dev.120.4.1017 ◽

1994 ◽

Vol 120 (4) ◽

pp. 1017-1025 ◽

Cited By ~ 17

Author(s):

M.H. Verlhac ◽

J.Z. Kubiak ◽

H.J. Clarke ◽

B. Maro

Keyword(s):

Cell Cycle ◽

Myelin Basic Protein ◽

Map Kinase ◽

Kinase Activity ◽

Basic Protein ◽

Chromatin Condensation ◽

Meiotic Maturation ◽

Protein Kinase Activity ◽

Microtubule Organization ◽

Kinase Activation

Oocyte meiotic maturation is triggered by different stimuli (hormones, unknown signals through cell interactions) in different species. These stimuli indirectly lead to the activation of a major cell cycle regulating activity, the maturation promoting factor (MPF). Other factors, such as the product of the proto-oncogene c-mos or enzymes of the MAP kinase family, are also involved in the process of maturation. MAP kinase activation occurs during meiotic maturation in oocytes from different species with different kinetics. The relationships between MPF activation and MAP kinase activation have been well studied in species such as clam and Xenopus. In this paper, we study the precise timing of MAP kinase activation (as measured by phosphorylation of exogenous myelin basic protein and shifts in mobility of ERK 1 and ERK 2) versus MPF activation (as measured by phosphorylation of exogenous histone H1) during mouse oocyte maturation and, in parallel, morphological events such as changes in microtubule organization and chromatin condensation. We observed that MAP kinase activation was delayed after MPF activation and that this activity persisted throughout maturation whereas MPF activity dropped between the two meiotic metaphases. After parthenogenetic activation of ovulated eggs, MAP kinase inactivation was very slow compared to MPF inactivation. During the first mitotic cell cycle, a rise in myelin basic protein kinase activity at M-phase was observed but it was not related to MAP kinase activation. Furthermore, microtubules and chromatin remained in a metaphase-like state during the complete period of maturation (including the period between the two meiotic metaphases) and a few hours after activation.(ABSTRACT TRUNCATED AT 250 WORDS)

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cAMP inhibits mitogen-activated protein (MAP) kinase activation and resumption of meiosis, but exerts no effects after spontaneous germinal vesicle breakdown (GVBD) in mouse oocytes

Reproduction Fertility and Development ◽

10.1071/rd99038 ◽

1999 ◽

Vol 11 (2) ◽

pp. 81 ◽

Cited By ~ 23

Author(s):

Q. Y. Sun ◽

Q. Lu ◽

H. Breitbart ◽

D. Y. Chen

Keyword(s):

Map Kinase ◽

Map Kinases ◽

Specific Inhibitor ◽

Germinal Vesicle ◽

Germinal Vesicle Breakdown ◽

Kinase Activation ◽

Protein Map ◽

Mitogen Activated Protein ◽

Kinase Phosphorylation ◽

Pkc Activation

Various signaling molecules have been implicated in the oocyte G2/MII transition, including protein kinase C (PKC), cAMP and mitogen-activated protein (MAP) kinases. However, the cross-talk among these signaling pathways has not been elucidated. The present study demonstrates that both germinal vesicle break down (GVBD) and MAP kinase phosphorylation (activation) are inhibited when intraoocyte cAMP is increased by treating the GV-intact oocytes with dibutyryl cyclic AMP (dbcAMP), forskolin, or isobutylmethylxanthine (IBMX). Okadaic acid, a specific inhibitor of protein phosphatase-1 and -2A, completely overcame this effect. Calphostin C, a specific inhibitor of PKC, accelerated both GVBD and MAP kinase phosphorylation, and this effect was attenuated by increased intraoocyte cAMP, whereas PKC activation inhibited these events. Once GVBD occurred, the progression of oocyte maturation and MAP kinase phosphorylation were independent of cAMP. These results indicate that an increase in intraoocyte cAMP, in synergy with PKC activation, initiates a cascade of events resulting in inhibition of MAP kinase phosphorylation and GVBD in the mouse oocyte.

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RHO-associated protein kinase alpha potentiates insulin-induced MAP kinase activation in Xenopus oocytes

Journal of Cell Science ◽

10.1242/jcs.112.13.2177 ◽

1999 ◽

Vol 112 (13) ◽

pp. 2177-2184 ◽

Cited By ~ 1

Author(s):

N. Ohan ◽

Y. Agazie ◽

C. Cummings ◽

R. Booth ◽

M. Bayaa ◽

...

Keyword(s):

Signal Transduction ◽

Protein Kinase ◽

Map Kinase ◽

Insulin Receptor ◽

Xenopus Oocytes ◽

Germinal Vesicle ◽

Insulin Receptor Substrate ◽

Germinal Vesicle Breakdown ◽

Kinase Activation ◽

Insulin Signal Transduction

We recently identified Xenopus Rho-associated protein kinase alpha (xROKalpha) as a Xenopus insulin receptor substrate-1 binding protein and demonstrated that the non-catalytic carboxyl terminus of xROKalpha binds Xenopus insulin receptor substrate-1 and blocks insulin-induced MAP kinase activation and germinal vesicle breakdown in Xenopus oocytes. In the current study we further examined the role of xROKalpha in insulin signal transduction in Xenopus oocytes. We demonstrate that injection of mRNA encoding the xROKalpha kinase domain or full length xROKalpha enhanced insulin-induced MAP kinase activation and germinal vesicle breakdown. In contrast, injection of a kinase-dead mutant of xROKalpha or pre-incubation of oocytes with an xROKalpha inhibitor significantly reduced insulin-induced MAP kinase activation. To further dissect the mechanism by which xROKalpha may participate in insulin signalling, we explored a potential function of xROKalpha in regulating cellular Ras function, since insulin-induced MAP kinase activation and germinal vesicle breakdown is known to be a Ras-dependent process. We demonstrate that whereas injection of mRNA encoding c-H-Ras alone induced xMAP kinase activation and GVBD in a very low percentage (about 10%) of injected oocytes, co-injection of mRNA encoding xROKalpha and c-H-Ras induced xMAP kinase activation and germinal vesicle breakdown in a significantly higher percentage (50-60%) of injected oocytes. These results suggest a novel function for xROKalpha in insulin signal transduction upstream of cellular Ras function.

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